Rupturable heat shield



1965 w.- VAN TINE ETAL 3,198,073

RUPTURABLE HEAT SHIELD Original Filed Feb. 8. 1961 INVENTOR. WILBUR VAN Tmz BY BERNARD L. KOTYUK United States Patent 6 l This invention generally relates to a protec 've end cap for containers of materials, which materials react in the presence of heat, and more particularly to a heat shield detachably secured to the exhaust of a missile launcher.

This application is a continuation of our copending application Serial No. 87,804, filed Feb. 8, 1961, now abandoned.

This invention is directed to an improved shield, the principal advantages of which are simplicity, positive securing engagement with a mounting member, and rapid yet easy assembly. The advantage of positive securing engagement is of particular importance whenever the shield is applied to the exchaust of a missile launcher wherein high pressures and temperatures pose a problem. The gases discharged upon the firing of a missile migrate or are reflected to adjacent launchers and in some instances the heat and pressures are sufficiently great to set off other missiles prematurely.

While it is important that the shield be sufficiently strong and reflective to afford protection to uniired missiles, it is also important that the shield be rupturable upon firing of its respective missile in order to allow the gases to exhaust. It is preferred that the shield rupture rather than slip from its secured position upon deton-ation of the charge in its respective launching tube so that the gases will be substantially uniformly dissipated.

Fire resistant and heat reflective cloths have been suggested heretofore as shields, however, these have proven to be unsatisfactory because considerable handling and time is required to mount the cloths upon the launcher end, some of which are 30 inches in diameter, and because no positive means is provided to deter slipping through the fastening ring. In order to mount the cloths, two men pull the cloth taut while a third man secures the fastening ring. Thus the quality of protection afforded by the shields is largely contingent upon the eiliciency of the workmen.

Therefore, it is an object of this invention to provide a heat protective cap which may be readily assembled and disassembled onto and from the open end of an enclosure.

It is another object of this invention to provide an arrangement wherein a heat protective cap is positively secured against slipping.

Still another object of this invention is to provide an end cap that has heat and flame resistant properties sufficient to Withstand conditions encountered in the launching of missiles.

A preferred embodiment of the apparatus of this invention is adapted for use in conjunction with a missile launcher in which a plurality of launching tubes are positioned adjacent to each other. In accordance with the invention, the exhaust ends of the tubes are provided with a heat protective cap molded of asbestos cloth reinforced with corrosion resistant metallic wire and coated with a fire resistant compound which may have a chloroprene base. The cap is in the form of an annulus or rim portion circumposing a flexible disc or body portion. The rim portion is sufficiently flexible to permit mounting over the terminal portion of the launcher tube and yet render the body portion taut. The annulus is also preferably or" Patented Aug. 3, 1%65 a U cross-sectional configuration to fit about a flange of the launching tube. The annulus is provided with an appendage having at least a segment of increased thickness, which may be in the form of a bulbous portion extending from and joined to one leg of the U. The appendage is preferably cored to form a sheath adapted to receive an asbestos draw-string for initial tightening about the tube end. A clamp band having force transmitting portions joined together by a constrictor band, circumposes the annulus and wedges the appendage to prevent slipping over the tube flange and from the constrictor band. The ends of the constrictor band are provided with take-up fastening means to detachably secure the band to the tube.

The novel features considered characteristic of this invention are set forth with particularity in t e appended claims. The invention itself, however, will be best understood fro mthe following description of specific embodiments when read in connection with the accompanying drawings in which similar numbers are employed to designate similar parts throughout and:

FIG. 1 is a schematic illustration of a missile launching station in which protective end caps of this invention are employed to shield the launcher tube openings;

PEG. 2 is a pictorial view of one embodiment of a protective end cap of this invention;

PEG. 3 is an enlarged fragmentary cross-sectional view of a tube flange and the protective end cap employed in connection therewith;

FIG. 4 is a plan view of one form of securing means that may be employed in connection with the invention; and

FIG. 5 is an enlarged fragmentary cross-sectional view of an alternate embodiment of this invention.

Referring to FIG. 1, a launching station iii comprising a plurality of launching tubes 12 for which the protective cap or shield of this invention is particularly adapted is schematically illustrated. As the charge (not shown) Within a tube 12 is detonated, very high temperatures and pressures are generated by the exhausting gases for at least a short period of time. Unless the adjacent launching tubes 12 are adequately shielded, the exhausted gases, migrating from the fired tube or reflected from the deck 16 of the launching station it will prematurely detonate the charges in the adjacent tubes 12. Tem eratures as high as 2000 F. for a period of 5 seconds may be encountered at the exhaust end 18 of launching tubes 12. in some installations. Thus to be effective, the shields 1d must be capable of withstanding these pressures and temperatures, but yet be rupturable to permit the gases gel-- erated within the tube being fired to be discharged. It has been determined that a shield having a minimum burst strength of 7 p.s.i. and the desired heat reflective properties will fulfill the requirements.

A protective shield 14 according to a preferred embodiment of this invention and as illustrated in more detail in FIGS. 2 and 3 comprises a central or disc portion 24? and a molded rim portion 2.2 terminating in a bulbous portion 24.

The disc or main body portion 20 is preferably of fireresistant fibers such as asbestos, 94%, Woven together and reinforced with corrosion-resistant metallic thread or wire, such as that commercially known as .008 diameter inconel, 1%, and impregnated with a fire-resistant compound having a rubber-like base material such as chloroprene, but retaining the flexible propensity characteristic of a cloth as opposed to the rigid propensity characteristic of thermoset resinous materials. The main body portion may be comprised of one layer 2h as shown in FIGS. 2 and 3, or of a plurality of layers 2% and Z0, bonded together such as shown in FIG. 5.

The rim portion 22 is preferably contoured and molded to assume a configuration corresponding to the radial terminal flange 32% forming a part of the launching tube 12. The terminal flange may be aflixed to the tube 12 as illustrated in FIG. 3 or form an integral part of the tube as a beaded or rolled rim having a U cross-sectional configuration as illustrated in FIG. 5. For economy in fabrication, the rim portion 22 is of the same material as the disc portion 2d. The terminal portion of rim 22 is doubled back upon itself and secured by stitching or other suitable means to form the bulbous section 24. The bulbous section 24 is adapted to receive initial retention or drawing means such as draw string 32. Draw string 32 is preferably made of asbestos cord in order to withstand the increased temperature encountered. However, other drawing or initial retention means, such as a garter spring 34 may also be employed within or adjacent to the bulbous portion 24. In some instances, particularly with large diameter shields, it may be desirable to provide intermittent transverse slots 25 about the periphery of bulbous section 24 to facilitate initial drawing and to prevent bulging or gathering of the material.

In use, the protective shield 14 is positioned about the terminal flange 39 of a tube 12; the initial retention means in the form of draw string 32 is drawn to pull the flexible disc portion 20 taut across the tube opening and to intermesh the molded rim portion 22 with the tube rim or flange St A releasable clamp band it) comprising actuator ring segments 31 and constrictor band 41 forming securing means, is then mounted over the rim 22 and drawn to cause the rim 22 to hug flange 3th closely. Fastening means 42 is also provided to draw and secure the ends of clamp band together. The fastening means may be in the form of a T-bolt i4 and slotted trunnion member 46 for receiving the T-bolt 44 which may be drawn by tightening nut 48.

The clamp band 49 preferably has a cross-sectional configuration corresponding to the rim 3th. The actuator ring segments 39, which serve as force transmitters when the ends of band 4t) are tightened, circumpose the molded rim 22 to wedge the bulbous portion or terminal end of increased thickness 24, and thereby deter slipping of the shield 14- upon detonation of the charge within the respective tube 12. With the arrangement provided by the instant invention, the skin or disc portion 26 instead of slipping will rupture and tend to dissipate the exhausting gases.

The possibility of attaining a preferred ruptured pattern may be enhanced by providing a disc having a zone or zones of less strength than the rest of the disc, as by using a disc of predetermined cross-sectional design so as to rupture at the zone of least thickness when the predetermined gas pressure is attained. In HG. 5 another method of maintaining the rupture pattern in a preferred zone is illustrated. Here the disc will tend to rupture at the outer periphery of disc portion 2% where there is but a single thickness or disc 29 comprising the body of the shield. Rupture along the periphery 21 of disc portion 20 may further be enhanced by scoring 23, or otherwise weakening the main disc portion Zn in a prestressed pattern corresponding to the periphery of disc portion 26'.

The advantages of the invention in simplicity, positiveness of securing, and rapid assembly and disassembly will be apparent to those skilled in the art from the foregoing description of the preferred embodiments of the invention. It will also be apparent to those skilled in the art that many modifications of structure may be made within the principles and scope of the invention which is not to be restricted except as necessitated by the prior art and by the spirit of the appended claims.

What we claim:

It. A rupturable heat shield capable of withstanding temperatures in the order of 2000 F. and adapted to be positioned over a flange portion of a missile launching tube, comprising: a resilient body portion fabricated of woven asbestos fibers impregnated with a fire-resistant compound having a rubber-like base material but retaining the flexible propensity of a cloth; a contoured rim integrally molded with and circumposing said body portion, said rim having a portion corresponding to the configuration of and adapted to intermesh with at least a portion of the flange portion; and an appendage joined to said rim portion and forming a sheath for receiving a draw string.

2. A rupturable heat shield as described in claim 1 wherein said resilient body has a bursting strength of at least 7 p.s.i.

3. A rupturable heat shield capable of withstanding temperatures in the order of 2000 F, and adapted to be positioned over a flange portion of a missile launching tube, comprising: a woven as estos body portion reinforced with metallic thread and impregnated with a chioroprene base material but retaining the flexible propensity of a cloth; a contoured rim integrally molded with and circumposing said body portion, said rim having a portion corresponding to the configuration of and adapted to intermesh with at least a portion of the flange portion; and an appendage joined to said rim portion and forming a sheath for receiving a draw string.

3. In combination with a missile launching tube containing a detonable charge and having a terminal portion of said tube defining a flange for receiving a rim, a rupturable heat shield comprising a heat reflective body portion covering the exhaust end of said tube, said body portion being fabricated of 94% asbestos fibers, 1% corrosion-resistant metallic thread, and a chloroprene ase material, a rim integrally molded with and circumposing said body portion, said rim having a portion corresponding to the configuration of and intermeshing with at least a portion of said flange, an appendage joined to said rim portion, at least a segment of said appendage having a thickness greater than said rim portion, said appendage also forming a sheath, a draw string positioned Within said sheath for drawing said appendage to said tube, and detachable securing means circumposing said rim portion and wedging said appendage to deter slipping of said rim between said flange and said securing means.

5. A rupturable heat shield capable of withstanding temperatures in the order of 2000 F. and adapted to be positioned over a flange portion of a missile launching tube, comprising: a woven asbestos body portion reinforced with metallic thread and impregnated with a chloroprene base material but retaining the flexible propensity of a cloth; and a contoured rim integrally molded with and circumposing said body portion, said rim having a portion corresponding to the configuration of and adapted to intermesh with at least a portion of the flange portion.

References Cited by the Examiner UNITED STATES PATENTS 2,511,481 6/50 Schneider 2995.7 X 2,866,731 12/58 Van Epp 15443 FORElGN PATENTS 578,034 6/59 Canada.

BENJAMIN A. BORCHELT, Primary Examiner. 

3. A RUPTURABLE HEAT SHIELD CAPABLE OF WITHSTANDING TEMPERATURES IN THE ORDER OF 2000*F. AND ADAPTED TO BE POSITIONED OVER A FLANGE PORTION OF A MISSILE LAUNCHING TUBE, COMPRISING: A WOVEN ASBESTOS BODY PORTION REINFORCED WITH METALLIC THREAD AND IMPREGNATED WITH A CHLOROPRENE BASE MATERIAL BUT RETAINING THE FLEXIBLE PROPENSITY OF A CLOTH; A CONTOURED RIM INTEGRALLY MOLDED WITH AND CIRCUMPOSING SAID BODY PORTION, SAID RIM HAVING A PORTION CORRESPONDING TO THE CONFIGURATION OF AND ADAPTED TO INTERMESH WITH AT LEAST A PORTION OF THE FLANGE PORTION; AND AN APPENDAGE JOINED TO SAID RIM PORTION AND FORMING A SHEATH FOR RECEIVING A DRAW STRING. 